A housing is always used when electrical components need to be shielded or protected from the outside world. The use of such a housing is conceivable, for example, in installation technology, safety technology, automation technology, wiring technology and measurement technology.
Depending on the application, the housing has options for sealing which are determined by the susceptibility of the electrical components. Depending on the protection class, the housing may be provided for protection against the ingress of moisture or spray water or against mechanical stress.
A further function of the housing resides in the fact that the conductors, such as cables, for example, can be fed to the electrical components in the required number. The conductor feed opening increases the complexity of the sealing problem. On the other hand, an easily accessible housing or housing part is advantageous for fitting purposes. As a result, the design of such a housing is a product of a compromise between ease of fitting and problems associated with sealing.
Such a housing is also used in connection with position switches and safety switches. Position switches likewise need to be connected to electrical conductors. This takes place, for example, directly or indirectly via ASI plug-type connectors (actuator/sensor interface plug-type connectors), which are connected to the electrical components, such as a switching element, for example. The position switch housing generally has one or more connection openings and a cover.
When connecting the conductors, the cover is removed in order to connect them to the switch element once they have been threaded in through the conductor openings. The conductor feed openings are also referred to as connection openings and are generally implemented as a standardized interface between the housing the and the surrounding environment of the installation. The standardized interface can in this case be in the form of a conductor screw connection, plug or the like.
Not only the housing or its component parts, but also the connection opening need to meet a plurality of preconditions. They need to protect the device interior against the ingress of foreign bodies and liquids and against other environmental influences. The sealtightness of the housing furthermore needs to correspond to national and international standards. In addition, the possibility of easy fitting of the connection lines is generally desirable.
DE 36 29 783 C2 has disclosed a closure for a housing having a cover part which can be fixed to a base part by way of a snap-action connection. The housing disclosed in the mentioned patent specification can be closed such that it is hermetically sealed at its upper opening side via the cover part. In addition, the housing has a separate conductor feed opening.